The fire began just before 3 a.m. at an abandoned building near 7th and Heinz Avenue in Berkeley, close to Aquatic Park.
Fire officials say there was a fire nearby possibly at a homeless encampment, but they're still determining the cause of the fire.
Flames were shooting through the roof of the industrial building in Berkeley. The roof collapsed in and firefighters doused the flames with water from above. Nobody was inside at the time of the fire, and no injuries have been reported.
VIDEO: Owner and community devastated after fire destroys popular Oakland bookstore, displaces residents
Owner and community devastated after fire destroys popular bookstore, displaces residents
Berkeley Fire Battalion Chief Bill Kehoe says more than 30 firefighters battled the blaze.
"We were not able to save this building but we were able to save the building that was attached to the back side that does have a fire wall which helps protect the fire from spreading into that building," Battalion Chief Kehoe said.
A fire captain said the neighboring vacant warehouse that was saved just had minimal water damage. He says the burned building didn't have tenants and is for lease. It has three units within it with a mix of warehouse and office space.
Amid the firefight, a power line also dropped, and crews had to navigate around that. It appears a transformer blew, and a van also caught on fire.
That van is where Ryan Six lives with his three dogs. He says they were sleeping when two people pulled up, warning them about the fire.
"I grabbed the dogs, got my backpack, my keys, my wallet, whatever I could," Six said. "I couldn't get my bike unfortunately and we got out of there."
The side of Six's van burned and with his windows blown out, the van unlivable.
Six says he has Stage 4 cancer, is undergoing treatment and has lived in two different vans outside that location for eight years.
"Hopefully maybe van three will be a standup van with a kitchen," he said. "This might be a blessing. I'm trying to look at it positively."
Six told ABC7 News he was going to REI to buy a tent for him and his dogs and plans to sleep on a sidewalk Wednesday night.
A GoFundMe has been set up to help Six.